Protector for electric circuits

ABSTRACT

A small electric fuse includes a small but rugged support which has the upper surface thereof relieved by a notch that is intermediate two metallic surfaces, includes a small fusible element which spans that notch and which has the ends thereof immediately adjacent those metallic surfaces, includes terminals which are soldered to those metallic surfaces and to that fusible element and which project outwardly beyond the ends of that support, and includes a housing which encases and is shrunk onto that support, those metallic surfaces, and the inner ends of those terminals. The inner ends of the terminals project upwardly from, as well as outwardly beyond, the metallic surfaces; and those inner ends initially space the inner surface of the housing away from the fusible element. The initial spacing of that inner surface from the upper faces of the metallic surfaces on the support is so great that the said inner surface either will not shrink into engagement with the fusible element or, if it does shrink into engagement with that fusible element, will be unable to apply destructive forces to that fusible element. The engagement between the housing and the support and the terminals effectively seals the opposite ends of the fuse against the entry of dirt, dust and other air-borne adulterants; and that housing is sufficiently rugged to withstand rough handling in the field.

United States Patent [191 Manker et al.

[4 1 Oct. 14, 1975 PROTECTOR FOR ELECTRIC CIRCUITS [75] Inventors:Clifford O. Manker, St. Louis; Craig L. McAlister, Florissant, both of[73] Assignee: McGraw-Edison Company, Elgin,

Ill.

[22] Filed: May 22, 1974 [21] Appl. No.: 471,846

Primary Examinerl-larold Broome Attorney, Agent, or FirmRogers, Ezell &Eilers [57] ABSTRACT A small electric fuse includes a small but ruggedsupport which has the upper surface thereof relieved by a notch that isintermediate two metallic surfaces, includes a small fusible elementwhich spans that notch and which has the ends thereof immediatelyadjacent those metallic surfaces, includes terminals which are solderedto those metallic surfaces and to that fusible element and which projectoutwardly beyond the ends of that support, and includes a housing whichencases and is shrunk onto that support, those metallic surfaces, andthe inner ends of those terminals. The inner ends of the terminalsproject upwardly from, as well as outwardly beyond, the metallicsurfaces; and those inner ends initially space the inner surface of thehousing away from the fusible element. The initial spacing of that innersurface from the upper faces of the metallic surfaces on the support isso great that the said inner surface either will not shrink intoengagement with the fusible element or, if it does shrink intoengagement with that fusible element, will be unable to applydestructive forces to that fusible element. The engagement between thehousing and the support and the terminals effectively seals the oppositeends of the fuse against the entry of dirt, dust and other air-borneadulterants; and that housing is sufficiently rugged to withstand roughhandling in the field.

15 Claims, 6 Drawing Figures PROTECTOR FOR ELECTRIC CIRCUITS FIELD OFTHE INVENTION The electric fuse provided by the present invention isintended to protect circuits which normally carry currents in the rangeof from one two-hundredth of an ampere to five amperes at voltages up to125 volts. Fuses which are intended to protect such circuits necessarilyhave extremely small fusible elements; and such fusible elements arefragile. Prior electric fuses, which were intended to protect suchcircuits, either utilized relatively-large rugged and sturdy bridges ofinsulating material to support the fusible elements thereof or fixedlysecured the fusible elements thereof to the interiors of glass casingswhich supported and protected those fusible elements. The use ofrelatively large bridges of insulating material necessarily made thesizes of the resulting fuses large; and the securement of fusibleelements to the interiors of glass casings is difficult and expensive.

DESCRIPTION OF THE PRIOR ART McAlister U.S. Pat. No. 2,576,405 disclosesan electric fuse wherein a bridge of insulating material supports asmall fusible element, McAlister U.S. Pat. No. 3,023,289 discloses anelectric fuse wherein small diameter fusible elements are mechanicallysecured to the ends of a glass casing by solder which bonds tometallized surfaces on the ends of those casings and McAlister U.S. Pat.No. 3,123,696 also uses solder to bond the ends of small fusibleelements to metallized surfaces at the opposite ends of glass casings.Urani U.S. Pat. No. 3,304,394 supports a small fusible element by solderwhich is bonded to metal eyelets that are fixedly secured within theends of glass casings, and Urani U.S. Pat. No. 3,348,007 supports smallfusible elements by bonding the ends thereof to metallic surfaces on abridge of insulating material. Urani U.S. Pat. No. 3,568,122 disclosessolder which bonds a fusible element to metallized surfaces on a bridgeof insulating material.

SUMMARY OF THE INVENTION The present invention provides a small electricfuse which includes a small but rugged support of insulating materialwhich has the upper surface thereof relieved by a notch that isintermediate two metallic surfaces, includes a small fusible elementwhich spans that notch and which has the ends thereof immediatelyadjacent those metallic surfaces, includes terminals which are solderedto those metallic surfaces and to that fusible element and which projectoutwardly beyond the ends of that support, and includes a housing whichencases and is shrunk into that support, those metallic surfaces, andthe inner ends of those terminals. The inner ends of the terminalsproject upwardly from, as well as outwardly beyond, the metallicsurfaces; and those inner ends initially space the inner surface of thehousing away from the fusible element. The initial spacing of that innersurface from the upper faces of the metallic surfaces on the support isso great that the said inner surface either will not shrink intoengagement with the fusible element or, if it does shrink intoengagement with that fusible element, will be unable to applydestructive forces to that fusible element. The engage ment between thehousing and the support and the terminals effectively seals the oppositeends of the fuse against the entry of dirt, dust and other air-borneadulterants; and that housing is sufficiently rugged to withstand roughhandling in the field. It is, therefore, an object of the presentinvention to provide a small electric fuse which has a support, a smallfusible element, terminals, and a housing which is shrunk onto thatsupport and those terminals.

The material used in the housing, of the fuse of the present invention,is a plastic material which responds to heat to evolve a gas that hasarc-extinguishing characteristics. That plastic material will tend toevolve such a gas whenever the fusible element fuses to open thecircuit; and hence the fuse provided by the present inventioncanextinguish any arc, that forms as the fusible element thereof fuses,before that are can adversely affect the plastic housing of that fuse.It is therefore, an object of the present invention to provide a smallelectric fuse which has a housing of plastic material which responds toheat to evolve a gas that has arcextinguishing characteristics.

The plastic housing of the present invention coacts with the support andwith the inner ends of the terminals to provide seals that prevent theentry of dirt, dust, and other air-borne adulterants. In addition, thatplastic housing is capable of withstanding sharp blows as well asfatique; and hence the electric fuse of the present invention is asealed fuse and is able to withstand rugged service. It is, therefore,an object of the present invention to provide a small electric fusewhich has a support, which has terminals that have their inner endssecured to that support, and which has a housing of plastic materialthat intimately engages that support and those inner ends to provideseals and that can withstand sharp blows and fatigue.

The plastic housing of the small electric fuse provided by the presentinvention is made from thermally stabilized plastic material which iscapable of providing a definitely limited amount of shrinking. Theamount of shrinking which that plastic housing can experience is limitedto keep that plastic housing from applying destructive forces to thefusible element of that fuse. It is, therefore, an object of the presentinvention to provide a housing for a small electric fuse which is madefrom thermally stabilized plastic material that is capable of providinga definitely limited amount of shrinking.

Other and further objects and advantages of the present invention shouldbecome apparent from examination of the drawing and accompanyingdescription.

In the drawing and accompanying description a preferred embodiment ofthe present invention is shown and described, but it is to be understoodthat the draw ing and accompanying description are for the purpose ofillustration only and do not limit the invention and that the inventionwill be defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, FIG. 1 is a plan viewof the support and of the fusible element of one preferred embodiment ofelectric fuse provided by the present invention,

FIG. 2 is a side elevational view of the support and of the fusibleelement of FIG. 1,

FIG. 3 is a broken plan view of the support and of the fusible elementof FIG. 1 after the inner ends of terminals have been disposed atop theends of that fusible element,

FIG. 4 is a sectional view through the support shown in FIG. 3 and it istaken along the plane indicated by the line 4-4 in FIG. 3,

FIG. 5 is a broken plan view of the support, fusible element andterminals of FIG. 3 after that fusible element and the inner ends ofthose terminals have been soldered to metallic surfaces on that support,and it shows by dotted lines a plastic housing telescoped over the saidsupport, fusible element and terminals, and

FIG. 6 is a broken sectional view through the support, terminals andplastic holding of FIG. 5, and it is taken along the plane indicated bythe line 66 in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to thedrawing in detail, the numeral generally denotes a support which is madeof insulating material; and the upper surface of that support isrelieved by having a notch 22 of arcuate configuration in the uppersurface thereof. In the said preferred embodiment, that support isbetween one hundred and ninety and two hundred and ten thousandths of aninch long, is five hundredths of an inch wide, and is four hundredths ofan inch thick. The notch 22 is between sixty and sixty-five thousandthsof an inch long and is about one hundredth of an inch deep at itscenter. The support 20 can be made of a ceramic material such assteatite or alumina, or it can be made of glass melamine, paper baseepoxy or some other stable insulating material. The basic requirementsof the support 20 are that it be sturdy, dimensionally stable, andessentially resistant to degrading due to heating or arcing.

The numerals 24'and 26 denote metallic surfaces which are provided onthe upper face of the support 20 and which are spaced apart by the notch22. In the said preferred embodiment, each of the metallic surfaces 24and 26 is about sixty-six thousandths of an inch long, about fivehundredths of an inch wide, and about one hundred and thirty-five onehundred thousandths of an inch thick. Although different metals could beused in forming the metallic surfaces 24 and 26, copper is preferred;because copper is easy to work, it is relatively inexpensive, and itreadily alloys with solder. The metallic surfaces 24 and'26 can beformed on the upper face of the support 20 by various techniques whichare known to those skilled in the art; and such techniques include metalcladding and electroplating. Those metallic surfaces preferably will beformed as parts of a continuous and homogeneous metallic surface, andthen those metallic surfaces will be defined by the machining of thenotch 22.

The numeral 28 denotes a metal terminal which is elongated and which iscircular in cross section. The numeral 30 denotes a planished end forthat terminal; and that planished end is offset radially from the axisof that terminal, as shown particularly by FIGS. 4 and 6. The planishingand offsetting of the end 30 of the terminal 28 preferably areaccomplished in a punch press or similar machine; and the offsettingoperation defines a shoulder, as shown by FIGS. 4 and 6. That shoulderserves as a stop which fixes the extent to which the planished end 30can overlie the metallic surface 24. The numeral 32 denotes a secondmetal terminal which is elongated and which is circular in crosssection. The numeral 34 denotes a planished end for that terminal; andthat planished end is offset radially from the axis of that terminal, asshown particularly by FIGS. 4 and 6. The planishing and offsetting ofthe end 34 of the terminal 32 preferably are accomplished in a punchpress or similar machine; and the offsetting operation defines ashoulder, as shown by FIGS. 4 and 6. That shoulder serves as a stopwhich fixes the extent to which the planished end 34 can overlie themetallic surface 26. As shown by FIGS. 2-6, the planished ends 30 and 34are spaced short distances longitudinally outwardly of the notch 22 inthe upper surface of the support 20. In the said preferred embodiment,each of the terminals 28 and 30 is made from tinned copper wire whichhas a diameter of twenty-five thousandths of an inch and each of thoseterminals is about one and five-eighths of an inch long. Each of theplanished ends 30 and 34 is about fifteen thousandths of an inch thickand is about thirty-two thousandths of an inch wide.

The numeral 36 denotes a fusible element which spans the notch 22 andwhich has the ends thereof overlying the metal surfaces 24 and 26. Thatfusible element will be small; and it will, for some ratings of electricfuses, be very small. For example, when the rating of the electric fuseis one two-hundredth of an ampere, the diameter of the fusible element36 will be thirty-five one millionths of an inch; and, when the ratingof that electric fuse is five amperes, the diameter of that fusibleelement will be twelve ten thousandths of an inch. That fusible elementpreferably will be made from silver, copper, or silverplated copper.Where the diameter of that fusible element must be very small, thatfusible element will preferably by made from a length of Wollaston wire.

The numeral 38 denotes solder which electrically bonds, and mechanicallyconnects, the left-hand end of the fusible element 36 and the planishedend 30 of the terminal 28 to the metallic surface 24. The numeral 40denotes solder which electrically bonds, and mechanically connects, theright-hand end of that fusible element and the planished end 34 of theterminal 32 to the metallic surface 26. The solder 38 provides such astrong mechanical'bond between the planished end 30 of terminal 28 andthe metallic surface 24 that neither a rivet nor any other form ofmechanical securement is required between that terminal and the support20. Similarly, the solder 40 provides such a strong mechanical bondbetween the planished end 34 of terminal 32 and the metallic surface 26that neither a rivet nor any other mechanical securement is requiredbetween the terminal 32 and the support 20.

The numeral 42 denotes a housing which is approximately ninethirty-seconds of an inch long, which has a nominal wall thickness oftwo-hundredths of an inch, and which has an initial inner diameter ofninety-three thousandths of an inch. In the said one preferredembodiment, the housing 42 is made from a military grade polyolefinheat-shrinkable tubing which is marketed by the Electronized ChemicalCorp. under the designation FP-30l. That plastic material is flexibleand flame retarding in nature; and it is made from irradiated,thermally-stabilized, modified polyolefin. As a result, that plasticmaterial can be shrunk only to a predetermined extent; and hence thathousing will tend to recover to a predetermined minimum dimension as itcools.

In making the electric fuse of the said preferred embodiment, thesupport 20 is initially a part of a large copperclad sheet of insulatingmaterial; and the notch 22 is formed by a routing operation. Thatrouting operation not only removes metal cladding but also removes someinsulating material as it forms the notch 22. The solder 38 and 40 isapplied to the metallic surfaces 24 and 26 as a layer after the notch 22has been formed as indicated by FIGS. 1-4; and then the fusible element36 is set in position to span the notch 22 and to have its endsoverlying the solder 38 and 40. The planished end 30 of the terminal 28is set in position above the left-hand end of the fusible element 36;and the shoulder between that planished end and the rest of thatterminal will abut the left-hand end of the support 20 to limit theextent to which that planished end can be moved inwardly of that end ofthat support. The planished end 34 of the terminal 32 is set in positionabove the right-hand end of the fusible element 36; and the shoulderbetween that planished end and the rest of that terminal will abut theright-hand end of the support 20 to limit the extent to which thatplanished end can be moved inwardly of that end of that support. At thistime, heat is applied to the planished ends 30 and 34 to cause thesolder 38 and 40 to flow as indicated by FIGS. 5 and 6; and the solder38 will electrically bond and mechanically secure the left-hand end offusible element 36 and the planished end 30 of terminal 28 to themetallic surface 24, while the solder 40 will electrically bondandmechanically secure the righthand end of that fusible element and theplanished end 34 of terminal 32 to the metallic surface 26. This meansthat the fusible element 36 will be spanning the notch 22, and will havethe ends thereof overlying the metallic surfaces 24 and 26 butunderlying the planished ends 30 and 34, respectively, of the terminals28 and 32. Consequently, the axis of the major portion of the fusibleelement will be displaced below the level of the upper surfaces of theplanished ends 30 and 34. Also, the axes of the portions of theterminals 28 and 32 which extend longitudinally outwardly beyond theends of the support 20 will be spaced even further below those uppersurfaces of those planished ends. In addition, the axes of thoseoutwardly-extending portions of the terminals 28 and 32 will begenerally coaxial with the support 20.

The housing 42 will then be telescoped over the outer portion of one ofthe terminals 28 and 32, and will thereafter be shifted into a positionwherein it will enclose the support 20, the metallic surfaces 24 and 26,the planished ends 30 and 34 of terminals 28 and 32, respectively, thefusible element 36, and the solder 38 and 40. At such time, the ends ofthe housing 42 will extend short distances outwardly beyond the ends ofthe support 20, and hence will encase the shoulders which are locatedbetween the planished ends 30 and 34 and the longitudinallyoutwardly-extending portions of the terminals 28 and 32, respectively.Heat will be applied to the housing 42; and that housing will respond tothat heat to shrink into intimate engagement with the bottom and sidesof the support 20, and also into intimate engagement with the upperfaces and sides of the planished ends 30 and 34 of the terminals 28 and32, respectively. In doing so, the material of that housing will formseals which will effectively resist the entry of dirt, dust and otherairborne adulterants.

The positioning of the left-hand end of the fusible element 36 betweenthe metallic surface 24 and the planished end 30 of the terminal 28, andthe positioning of the right-hand end of that fusible element betweenthe metallic surface 26 and the planished end 34 of the terminal 32,will enable those planished ends to initially space the inner surface ofthe housing 42 away from that fusible element. Moreover, in the saidpreferred embodiment, the initial spacing between the inner surface ofthat housing and the fusible element 36 is great enough to keep thatinner surface from moving into engagement with that fusible elementduring the shrinking of that housing. This is desirable; because it notonly avoids the application of stresses to that fusible element duringthe shrinking of the housing 42, but it also avoids any contact betweenthe inner surface of that housing and that fusible element which couldaffect the rating of the electric fuse. The overall result is that wherethe inner surface of the housing 42 continues to remain out ofengagement with all portions of the fusible element 36, that fusibleelement will not be subjected to destructive stresses during theshrinking of that housing, and that fusible element will be able toprovide a predictable rating for the electric fuse.

If dimensional considerations were to require the use of extremely thinplanished ends 30 and 34, respectively, for the terminals 28 and 32, andif the inner surface of the housing 42 were to tend to engage andstretch the fusible element 36 during the shrinking of that housing, thefusible element 36 could be bowed downwardly toward the bottom of thenotch 22 prior to the time that fusible element was soldered to themetallic surfaces 24 and 26. In such event, the ends of that notch wouldbe able to coact with even very thin planished ends 30 and 34 to keepthe inward movement of the inner surface of the housing 42, during theshrinking of the material of that housing, from applying hurtfulstresses to the fusible element 36.

The fusible element 36 will respond to any current flowing through it togenerate heat; and that heat will make the longitudinal center of thatfusible element hotter than any other portion of that fusible element.Because the notch 22 is arcuate in side elevation, and because thedeepest portion of that notch is in register with the longitudinalcenter of that part of the fusible element 36 which spans that notch,there will be an air space adjacent at least a portion of the surfacearea of that part of that fusible element. That air space will provide apredictable rate of heat radiation from that portion of the surface areaof the longitudinal center of that part of the fusible element 36 whichspans the notch 22.

As long as the current flowing through the electric fuse remains below apredetermined level, the fusible element 36 will remain intact. However,if the current flowing through that electric fuse rises to anobjectionable level, that fusible element will fuse and will therebyintercept the flow of current through that electric fuse with consequentinterruption of the flow of current through the circuit protected bythat electric fuse.

The housing 42 will protect the fusible element 36 from injury due tosharp blows or abrasion; because the material of that housing is sturdy,is not brittle, and has a high resistance to fatique. In addition, thathousing will help the solder 38 and 40 resist forces which could tend toshift the terminals 28 and 32, respectively, relative to the metallicsurfaces 24 and 26. Moreover, that housing will protect the jointsbetween the metallic surfaces 24 and 26 and the upper face of thesupport 20, and thereby will help make the electric fuse stronglyresistant to damage and injury.

The present invention thus makes it possible to provide an extremelysmall but very rugged electric fuse. Specifically, the overall length ofthe housing 42 can be as small as nine thirty-seconds of an inch plus orminus one thirty-second of an inch, the width of that housing can beabout one-tenth of an inch, and the height of that housing can be aboutone-tenth of an inch.

The material of which the housing 42 is made can respond to the presenceof an electrical arc, which develops as the fusible element 36 fuses, toevolve a gas or vapor which will help quench that arc. Also, theplanished ends 30 and 34, respectively, of the terminals 28 and 32 willhave sufficient mass, relative to the small mass of the fusible element36, to enable those planished ends to act as arc-cooling arcingcontacts. Because of these facts, and also because the material of thehousing 42 is not brittle, the electric fuse provided by the presentinvention can open electrical circuits to which one hundred andtwenty-five volts are applied; and it can open those electrical circuitsand still leave the housing 42 unbroken.

The offsetting of the planished inner ends of the terminals 28 and 32from the axes of the outwardlyextending portions of those terminalsenables the axes of those outwardly-extending portions to be close tothe axis of the support 20. As a result, the extent to which any portionof the electric fuse projects radially outwardly beyond the outersurface of the outwardlyextending portion of either of the terminals 28and 32 is just a few thousandths of an inch.

When the housing 42 is heated to shrink it, all portions of that housingwill shrink. However, if desired, local heating of specific areas of thehousing 42 could be provided to effect shrinking of just those portionsof that housing. For example, if desired, the ends of the housing 42could be heated to shrink them into sealing engagement with the ends ofthe support and with the planished ends and 34, respectively, of theterminals 28 and 32. In such event, the middle portion of the housing 42could retain its initial dimensions, and thus could make certain thatthe inner surface thereof was spaced an appreciable distance from allportions of the fusible element 36.

The plastic material used in forming the housing 42 can be obtained in arange of colors; and that is desirable, because it permits color codingof the electric fuses provided by the present invention. Color coding ofthose electric fuses is very desirable, because the very small sizes ofthose electric fuses make it very difficult to mark those electric fuseswith their ampere ratings.

Whereas the drawing and accompanying description have shown anddescribed a preferred embodiment of the present invention, it should beapparent to those skilled in the art that various changes may be made inthe form of the invention without affecting the scope thereof.

What we claim is:

1. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, and ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsextending outwardly through and beyond the ends of said housing ofreadily shrinkable material to have the outer ends thereof engageablewith spaced-apart components of an electric circuit to be protected bysaid electric fuse, said terminals having said inner ends thereof spacedapart a predetermined distance, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit, said spacing apart of said innerends of said terminals acting to minimize or prevent burning of saidinner ends of said terminals when said fusible element fuses to opensaid electric circuit.

2. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsextending outwardly through and beyond the ends of said housing ofreadily shrinkable material to have the outer ends thereof engageablewith spaced-apart components of an electric circuit to be protected bysaid electric fuse, said terminals having said inner ends thereof spacedapart a predetermined distance, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit, said spacing apart of said innerends of said terminals acting to minimize or prevent burning of saidinner ends of said terminals when said fusible element fuses to opensaid electric circuit, the first said terminal having said inner endthereof engaging and holding said one end of said support and havingsaid outer end thereof extending outwardly beyond said one end of saidsupport, said second terminal having said inner end thereof engaging andholding said other end of said support and having said outer end thereofextending outwardly beyond said other end of said support, said outerend of said first said terminal being offset from said inner end of saidfirst said terminal to enable said outer end of said first said terminalto be generally coaxial with said support although said inner end ofsaid first said terminal is displaced laterally from the axis of saidsupport, and said outer end of said second terminal being offset fromsaid inner end of said second terminal to enable said outer end of saidsecond terminal to be generally coaxial with said support although saidinner end of said second terminal is displaced laterally from said axisof said support.

3. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsextending outwardly through and beyond the ends of said housing ofreadily shrinkable material to have the outer ends thereof engageablewith spaced-apart components of an electric circuit to be protected bysaid electric fuse, said terminals having said inner ends thereof spacedapart a predetermined distance, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit, said spacing apart of said innerends of said terminals acting to minimize or prevent burning of saidinner ends of said terminals when said fusible element fuses to opensaid electric circuit, the first said terminal having an inner end thatengages said support and having an outer portion that extends outwardlybeyond said support, said second terminal having an inner end thatengages said support and having an outer portion that extends outwardlybeyond said support, said inner end of said first said terminal beingplanished to provide a large area of engagement between said inner endof said first said terminal and said one end of said support, said innerend of said second terminal being planished to provide a large area ofengagement between said inner end of said second terminal and said otherend of said support, said planished inner end of said first saidterminal being wider but thinner than an outer portion of said firstsaid terminal, and said planished inner end of said second terminalbeing wider but thinner than an outer portion of said second terminal.

4. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsbeing connectable to an electric circuit, said inner ends of saidterminals being exposed at the same side of said support, said fusibleelement having the effective length thereof disposed at said side ofsaid support, said terminals having said inner ends thereof spaced apartaxially of said support a predetermined distance, said fusible elementresponding to a potentially-hurtful overload of predetermined durationto fuse and thereby open said electric circuit, said predetermineddistance by which said inner ends of said terminals are spaced apartbeing substantially equal to said effective length of said fusibleelement, a portion of said inner end of said first said terminalextending laterally outwardly of one end of said fusible element to holdthe corresponding portion of the inner surface of said housing ofreadily shrinkable material laterally outwardly of said one end of saidfusible element, and a portion of said inner end of said second terminalextending laterally outwardly of the other end of said fusible elementto hold the corresponding portion of said inner surface of said housingof readily shrinkable material laterally outwardly of said other end ofsaid fusible element, and said spacing apart of said inner ends of saidterminals acting to minimize or prevent burning of said inner ends ofsaid terminals when said fusible element fuses to open said electriccircuit.

5. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsbeing connectable to an electric circuit, said inner ends of saidterminals being exposed at the same side of said support, said fusibleelement having the effective length thereof disposed at said side ofsaid support, said terminals having said inner ends thereof spaced apartaxially of said support a predetermined distance, said fusible elementresponding to a potentially-hurtful overload of predetermined durationto fuse and thereby open said electric circuit, a portion of said innerend of the first said terminal extending laterally outwardly of one endof said fusible element, a portion of said inner end of said secondterminal extending laterally outwardly of the other end of said fusibleelement, said portions of said inner ends of said terminals extendinglaterally outwardly of said ends of said fusible element far enough tohold said inner surface of said housing of readily shrinkable materialout of engagement with said effective length of said fusible element,said spacing apart of said inner ends of said terminals acting tominimize or prevent burning of said inner ends of said terminals whensaid fusible element fuses to open said electric circuit.

6. An electric fuse which comprises a support, said support having ametallic surface adjacent one end thereof, said support having a secondmetallic surface adjacent the other end thereof, a terminal adjacentsaid one end of said support, a second terminal adjacent said other endof said support, a fusible element electrically connecting saidterminals, a housing of readily shrinkable material which encloses andprotects said fusible element, said housing of readily shrinkablematerial having portions thereof shrunk into engagement with andenclosing portions of said support and portions of the inner ends ofsaid terminals, said terminals being connectable to an electric circuit,said inner ends of said terminals being exposed at the same side of saidsupport, said fusible element having the effective length thereofdisposed at said side of said support, a portion of said inner end ofthe first said terminal being in register with the first said metallicsurface but one end of said fusible element being interposed betweensaid first said metallic surface and said portion of said inner end ofsaid first said terminal, and a portion of said inner end of said secondterminal being in register with said second metallic surface but theother end of said fusible element being interposed between said secondmetallic surface and said portion of said inner end of said secondterminal, said portions of said inner ends of said terminals beingdisposed between said ends of said fusible element and the inner surfaceof said housing of readily shrinkable material and acting to hold saidinner surface of said housing of readily shrinkable material out ofengagement with said ends of said fusible element, said fusible elementresponding to a potentially-hurtful overload of predetermined durationto fuse and thereby open said electric circuit.

7. An electric fuse which comprises a support, said support having ametallic surface adjacent one end thereof, said support having a secondmetallic surface adjacent the other end thereof, a terminal adjacentsaid one end of said support, a second terminal adjacent said other endof said support, a fusible element electrically connecting saidterminals, a housing of readily shrinkable material which encloses andprotects said fusible element, said housing of readily shrinkablematerial having portions thereof shrunk into engagement with andenclosing portions of said support and portions of the inner ends ofsaid terminals, said terminals being connectable to an electric circuit,said inner ends of said terminals being exposed at the same side of saidsupport, said fusible element having the effective length thereofdisposed at said side of said support, a portion of said inner end ofthe first said terminal being in register with the first said metallicsurface but one end of said fusible element being interposed betweensaid first said metallic surface and said portion of said inner end ofsaid first said terminal, a portion of said inner end of said secondterminal being in register with said second metallic surface but theother end of said fusible element being interposed between said secondmetallic surface and said portion of said inner end of said secondterminal, said portions of said inner ends of said terminals beingdisposed between said ends of said fusible element and the inner surfaceof said housing of readily shrinkable material and acting to hold saidinner surface of said housing of readily shrinkable material out ofengagement with said ends of said fusible element, said portions of saidinner ends of said terminals holding said inner surface of said housingof readily shrinkable material against movement into an i engagementwith any portion of said effective length of said fusible element whichcould apply destructive forces to said effective length of said fusibleelement, said fusible element responding to a potentially-ihurtfuloverload of predetermined duration to fuse and thereby open saidelectric circuit.

8. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and portions of the inner ends of said terminals, saidterminals extending outwardly through and beyond the ends of saidhousing of readily shrinkable material, said terminals having said innerends thereof spaced apart a predetermined distance, said fusible elementresponding to a potentially-hurtful overload of predetermined durationto fuse and thereby open said electric circuit, said housing of saidreadily shrinkable material having the outer ends thereof engagingportions of said terminals which are adjacent to but which extendoutwardly from said ends of said support, said portions of saidterminals which are adjacent to but which extend outwardly from saidends of said support having cross sections which are only smallfractions of the cross sections of said ends of said support, saidsupport being acircular in cross section, said terminals making saidcross sections of said ends of said support irregular, and said portionsof said housing of readily shrinkable material closely engaging saidportions of said terminals which are adjacent to but which extendoutwardly from said ends of said support and also closely engaging saidends of said support despite the irregularity of said ends of saidsupport and despite the disparity between the cross sections of saidends of said support and the cross sections of said portions of saidterminals which are adjacent to but which extend outwardly from saidends of said support, the engagements between said portions of saidhousing of readily shrinkable material and said portions of saidterminals which are adjacent to but which extend outwardly from saidends of said support resisting tilting of said terminals relative to theaxis of said support, and thereby helping said terminals remain inassembled relation with said support.

9. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and portions of the inner ends of said terminals, saidterminals being connectable to an electric circuit, said inner ends ofsaid terminals being exposed at the same side of said support, saidfusible element having the effective length thereof disposed at saidside of said support, a portion of said side of said support which isintermediate said terminals being relieved by a notch, said effectivelength of said fusible element spanning said notch of said side of saidsupport and thereby being held out of direct engagement with said sideof said support, and said inner ends of said terminals extendinglaterally outwardly beyond said side of said support to keep said innersurface of said housing of readily shrinkable material from applyingdestructive forces to said effective length of said fusible element,whereby said effective length of said fusible element is out ofengagement with said notch of said side of said support and is notsubjected to destructive forces by said inner surface of said housing ofreadily shrinkable material.

10. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsextending outwardly through and beyond the ends of said housing ofreadily shrinkable material and being adapted to hold said support, saidterminals being connectable to an electric circuit, said terminalshaving said inner ends thereof spaced apart a predetermined distance,said fusible element responding to a potentially-hurtful overload ofpredetermined duration to fuse and thereby open said electric circuit,said support having a metallic surface adjacent said one end thereof,

said support having a second metallic surface adjacent said other endthereof, a portion of said inner end of the first said terminal beingplanished and being in register with the first said metallic surface,said portion of said inner end of said first said terminal being bondedto said first said metallic surface in electrical conducting relation, aportion of said inner end of said second terminal being planished andbeing in register with said second metallic surface, said portion ofsaid inner end of said second terminal being bonded to said secondmetallic surface in electrical conducting relation, said first saidmetallic surface having a large face-to-face engagement with said oneend of said support, said planished portion of said inner end of saidfirst said terminal having a relatively large face-to-face engagementwith said first said metallic surface, said second metallic surfacehaving a large face-to-face engagement with said other end of saidsupport, said planished portion of said inner end of said secondterminal having a relatively large face-to-face engagement with saidsecond metallic surface, the ends of said housing of readily shrinkablematerial closely engaging those portions of said terminals which areadjacent to and which extend outwardly beyond said ends of said support,the close engagements between said ends of said housing of readilyshrinkable material and said portions of said terminals which areadjacent to and which extend outwardly beyond said ends of said supportcoacting with said face-to-face engagements between said inner ends ofsaid terminals and said metallic surfaces and also coacting with saidface-to-face engagements between said metallic surfaces and said ends ofsaid support to resist tilting of said terminals relative to the axis ofsaid support, and thereby helping to maintain said terminals inassembled relation with said support.

11. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and portions of the inner ends of said terminals, saidterminals being connectable to an electric circuit, the first saidterminal having an inner portion that is in register with and is fixedlysecured to said one end of said support and having an outer portion thatextends outwardly through said housing of readily shrinkable materialand beyond said one end of said support and beyond one end of saidhousing of readily shrinkable material to be adapted to hold said oneend of said support, said second terminal having an inner portion thatis in register with and is fixedly secured to said other end of saidsupport and having an outer portion that extends outwardly through saidhousing of readily shrinkable material and beyond said other end of saidsupport and beyond the other end of said housing of readily shrinkablematerial to be adapted to hold said other end of said support, saidhousing of readily shrinkable material engaging said inner portions ofsaid terminals, and said ends of said housing of readily shrinkablematerial extending outwardly beyond said ends of said support to encloseand intimately engage a part of each of said outer portions of saidterminals, the intimate engagement between said ends of said housing ofreadily shrinkable material and said parts of said outer portions ofsaid terminals enabling said housing of readily shrinkable material toresist tilting of said terminals relative to the axis of said supportand thereby helping prevent separation of said terminals from saidsupport.

12. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsbeing connectable to an electric circuit, said terminals having saidinner ends thereof spaced apart axially of said support a predetermineddistance, said fusible element responding to a potentially-hurtfuloverload of predetermined duration to fuse and thereby open saidelectric circuit, said predetermined distance by which said inner endsof said terminals are spaced apart being substantially equal to theeffective length of said fusible element, the cross section of saidfusible element being just a small fraction of the cross section of saidinner end of either of said terminals, whereby said inner ends of saidterminals have sufficient mass to cool any are which forms as saidfusible element fuses to open the circuit, and said spacing apart ofsaid inner ends of said terminals acting to minimize or prevent burningof said inner ends of said terminals when said fusible element fuses toopen said electric circuit.

13. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and portions of the inner ends of said terminals, the firstsaid terminal having an inner end that is in register with and isfixedly secured to said one end of said support and having an outerportion that extends outwardly through said housing of readilyshrinkable material and beyond said one end of said support and beyondone end of said housing of readily shrinkable material to be connectableto an electric circuit, said second terminal having an inner end that isin register with and is fixedly secured to said other end of saidsupport and having an outer portion that extends outwardly through saidhousing of readily shrinkable material and beyond said other end of saidsupport and beyond the other end of said housing of readily shrinkablematerial to be connectable to said electric circuit, a shoulder in saidfirst said terminal which is intermediate said inner end and said outerportion of said first said terminal, a shoulder in said second terminalwhich is intermediate said inner end and said outer portion of saidsecond terminal, and said housing of readily shrinkable materialintimately engaging said inner ends and said shoulders of said terminalsplus parts of said terminals which are outward of but which areimmediately adjacent said ends of said support, the intimate engagementsbetween said housing of readily shrinkable material and said inner endsand said shoulders and said parts of said terminals enabling saidhousing of readily shrinkable material to resist tilting of saidterminals relative to the axis of said support and thereby helpingprevent separation of said terminals from said support.

14. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and portions of the inner ends of said terminals, the firstsaid terminal having an inner end that is in register with and overlapsand is fixedly secured to said one end of said support and having anouter portion that extends outwardly through said housing of readilyshrinkable material and beyond said one end of said support and beyondone end of said housing of readily shrinkable material to be connectableto an electric circuit,

said second terminal having an inner end that is in register with andoverlaps and is fixedly secured to said other end of said support andhaving an outer portion that extends outwardly through said housing ofreadily shrinkable material and beyond said other end of said supportand beyond the other end of said housing of readily shrinkable materialto be connectable to said electric circuit, said inner end of said firstsaid terminal being planished to provide a large area of securementbetween said inner end of said first said terminal and said one end ofsaid support, said inner end of said second terminal being planished toprovide a large area of securement between said inner end of said secondterminal and said other endof said support, a shoulder in said firstsaid terminal which is intermediate said inner end and said outerportion of said first said terminal, a shoulder in said second terminalwhich is intermediate said inner end and said outer portion of saidsecond terminal, said shoulder in said first said terminal abutting saidone end of said support to limit the extent to which said planishedinner end of said first said terminal overlaps said one end of saidsupport, said shoulder in said second terminal abutting said other endof said support to limit the extent to which said planished inner end ofsaid second terminal overlaps said other end of said support, and saidhousing of readily shrinkable material intimately engaging said innerends and said shoulders of said terminals plus parts of said terminalswhich are outward of but which are immediately adjacent said ends ofsaid support, the intimate engagement between said housing of readilyshrinkable material and said inner ends and said shoulders and saidparts of said terminals enabling said housing of readly shrinkable material to resist tilting of said terminals relative to the axis of saidsupport and therebyhelping prevent separation of said terminals fromsaid support.

15. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, anotch in one side of said support which is spaced inwardly from saidends of said support and which is in register with the effective lengthof said fusible element, a housing of readily shrinkable material whichencloses and protects said fusible element, said housing of readilyshrinkable material having portions thereof shrunk into engagement withand enclosing portions of said support and portions of the inner ends ofsaid terminals, said I terminals being connectable to an electriccircuit, said inner ends of said terminals being exposed at said side ofsaid support, said fusible element having said effective length thereofdisposed at said side of said support, said inner ends of said terminalsacting to hold the inner surface of said housing of shrinkable materialout of engagement with said ends of said fusible element, said innerends of said terminals also holding said inner surface of said housingof shrinkable material against movement into and engagement with anyportion of said effective length of said fusible element which couldapply destructive forces to said effective length of said fusibleelement, said notch being arcuate in side elevation, the deepest portionof said notch being adjacent the longitudinal center of said effectivelength of said fusible element, and said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit.

1. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, and ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsextending outwardly through and beyond the ends of said housing ofreadily shrinkable material to have the outer ends thereof engageablewith spaced-apart components of an electric circuit to be protected bysaid electric fuse, said terminals having said inner ends thereof spacedapart a predetermined distance, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit, said spacing apart of said innerends of said terminals acting to minimize or prevent burning of saidinner ends of said terminals when said fusible element fuses to opensaid electric circuit.
 2. An electric fuse which comprises a support, aterminal adjacent one end of said support, a second terminal adjacentthe other end of said support, a fusible element electrically connectingsaid terminals, a housing of readily shrinkable material which enclosesand protects said fusible element, said housing of readily shrinkablematerial having portions thereof shrunk into engagement with andenclosing portions of said support and of the inner ends of saidterminals, said terminals extending outwardly through and beyond theends of said housing of readily shrinkable material to have the outerends thereof engageable with spaced-apart components of an electriccircuit to be protected by said electric fuse, said terminals havingsaid inner ends thereof spaced apart a predetermined distance, saidfusible element responding to a potentially-hurtful overload ofpredetermined duration to fuse and thereby open said electric circuit,said spacing apart of said inner ends of said terminals acting tominimize or prevent burning of said inner ends of said terminals whensaid fusible element fuses to open said electric circuit, the first saidterminal having said inner end thereof engaging and holding said one endof said support and having said outer end thereof extending outwardlybeyond said one end of said support, said second terminal having saidinner end thereof engaging and holding said other end of said supportand having said outer end thereof extending outwardly beyond said otherend of said support, said outer end of said first said terminal beingoffset from said inner end of said first said terminal to enable saidouter end of said first said terminal to be generally coaxial with saidsupport although said inner end of said first said terminal is displacedlaterally from the axis of said support, and said outer end of saidsecond terminal being offset from said inner end of said second terminalto enable said outer end of said second terminal to be generally coaxialwith said support although said inner end of said second terminal isdisplaced laterally from said axis of said support.
 3. An electric fusewhich comprises a support, a terminal adjacent one end of said support,a second terminal adjacent the other end of said support, a fusibleelement electrically connecting said terminals, a housing of readilyshrinkable material which encloses and protects said fusible element,said housing of readily shrinkable material having portions thereofshrunk into engagement with and enclosing portions of said support andof the inner ends of said terminals, said terminals extending outwardlythrough and beyond the ends of said housing of readily shrinkablematerial to have the outer ends thereof engageable with spaced-apartcomponents of an electric circuit to be protected by said electric fuse,said terminals having said inner ends thereof spaced apart apredetermined distance, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit, said spacing apart of said innerends of said terminals acting to minimize or prevent burning of saidinner ends of said terminals when said fusible element fuses to opensaid electric circuit, the first said terminal having an inner end thatengages said support and having an outer portion that extends outwardlybeyond said support, said second terminal having an inner end thatengages said support and having an outer portion that extends outwardlybeyond said support, said inner end of said first said terminal beingplanished to provide a large area of engagement between said inner endof said first said terminal and said one end of said support, said innerend of said second terminal being planished to provide a large area ofengagement between said inner end of said second terminal and said otherend of said support, said planished inner end of said first saidterminal being wider but thinner than an outer portion of said firstsaid terminal, and said planished inner end of said second terminalbeing wider but thinner than an outer portion of said second terminal.4. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and of the inner ends of said terminals, said terminalsbeing connectable to an electric circuit, said inner ends of saidterminals being exposed at the same side of said support, said fusibleelement having the effective length thereof disposed at said side ofsaid support, said terminals having said inner ends thereof spaced apartaxially of said support a predetermined distance, said fusible elementresponding to a potentially-hurtful overload of predetermined durationto fuse and thereby open said electric circuit, said prEdetermineddistance by which said inner ends of said terminals are spaced apartbeing substantially equal to said effective length of said fusibleelement, a portion of said inner end of said first said terminalextending laterally outwardly of one end of said fusible element to holdthe corresponding portion of the inner surface of said housing ofreadily shrinkable material laterally outwardly of said one end of saidfusible element, and a portion of said inner end of said second terminalextending laterally outwardly of the other end of said fusible elementto hold the corresponding portion of said inner surface of said housingof readily shrinkable material laterally outwardly of said other end ofsaid fusible element, and said spacing apart of said inner ends of saidterminals acting to minimize or prevent burning of said inner ends ofsaid terminals when said fusible element fuses to open said electriccircuit.
 5. An electric fuse which comprises a support, a terminaladjacent one end of said support, a second terminal adjacent the otherend of said support, a fusible element electrically connecting saidterminals, a housing of readily shrinkable material which encloses andprotects said fusible element, said housing of readily shrinkablematerial having portions thereof shrunk into engagement with andenclosing portions of said support and of the inner ends of saidterminals, said terminals being connectable to an electric circuit, saidinner ends of said terminals being exposed at the same side of saidsupport, said fusible element having the effective length thereofdisposed at said side of said support, said terminals having said innerends thereof spaced apart axially of said support a predetermineddistance, said fusible element responding to a potentially-hurtfuloverload of predetermined duration to fuse and thereby open saidelectric circuit, a portion of said inner end of the first said terminalextending laterally outwardly of one end of said fusible element, aportion of said inner end of said second terminal extending laterallyoutwardly of the other end of said fusible element, said portions ofsaid inner ends of said terminals extending laterally outwardly of saidends of said fusible element far enough to hold said inner surface ofsaid housing of readily shrinkable material out of engagement with saideffective length of said fusible element, said spacing apart of saidinner ends of said terminals acting to minimize or prevent burning ofsaid inner ends of said terminals when said fusible element fuses toopen said electric circuit.
 6. An electric fuse which comprises asupport, said support having a metallic surface adjacent one endthereof, said support having a second metallic surface adjacent theother end thereof, a terminal adjacent said one end of said support, asecond terminal adjacent said other end of said support, a fusibleelement electrically connecting said terminals, a housing of readilyshrinkable material which encloses and protects said fusible element,said housing of readily shrinkable material having portions thereofshrunk into engagement with and enclosing portions of said support andportions of the inner ends of said terminals, said terminals beingconnectable to an electric circuit, said inner ends of said terminalsbeing exposed at the same side of said support, said fusible elementhaving the effective length thereof disposed at said side of saidsupport, a portion of said inner end of the first said terminal being inregister with the first said metallic surface but one end of saidfusible element being interposed between said first said metallicsurface and said portion of said inner end of said first said terminal,and a portion of said inner end of said second terminal being inregister with said second metallic surface but the other end of saidfusible element being interposed between said second metallic surfaceand said portion of said inner end of said second terminal, saidportions of said inner ends of said terminals being disposed betweensaid ends of said fusible element and the inner surface of said housingof readily shrinkable material and acting to hold said inner surface ofsaid housing of readily shrinkable material out of engagement with saidends of said fusible element, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit.
 7. An electric fuse which comprisesa support, said support having a metallic surface adjacent one endthereof, said support having a second metallic surface adjacent theother end thereof, a terminal adjacent said one end of said support, asecond terminal adjacent said other end of said support, a fusibleelement electrically connecting said terminals, a housing of readilyshrinkable material which encloses and protects said fusible element,said housing of readily shrinkable material having portions thereofshrunk into engagement with and enclosing portions of said support andportions of the inner ends of said terminals, said terminals beingconnectable to an electric circuit, said inner ends of said terminalsbeing exposed at the same side of said support, said fusible elementhaving the effective length thereof disposed at said side of saidsupport, a portion of said inner end of the first said terminal being inregister with the first said metallic surface but one end of saidfusible element being interposed between said first said metallicsurface and said portion of said inner end of said first said terminal,a portion of said inner end of said second terminal being in registerwith said second metallic surface but the other end of said fusibleelement being interposed between said second metallic surface and saidportion of said inner end of said second terminal, said portions of saidinner ends of said terminals being disposed between said ends of saidfusible element and the inner surface of said housing of readilyshrinkable material and acting to hold said inner surface of saidhousing of readily shrinkable material out of engagement with said endsof said fusible element, said portions of said inner ends of saidterminals holding said inner surface of said housing of readilyshrinkable material against movement into an engagement with any portionof said effective length of said fusible element which could applydestructive forces to said effective length of said fusible element,said fusible element responding to a potentially-hurtful overload ofpredetermined duration to fuse and thereby open said electric circuit.8. An electric fuse which comprises a support, a terminal adjacent oneend of said support, a second terminal adjacent the other end of saidsupport, a fusible element electrically connecting said terminals, ahousing of readily shrinkable material which encloses and protects saidfusible element, said housing of readily shrinkable material havingportions thereof shrunk into engagement with and enclosing portions ofsaid support and portions of the inner ends of said terminals, saidterminals extending outwardly through and beyond the ends of saidhousing of readily shrinkable material, said terminals having said innerends thereof spaced apart a predetermined distance, said fusible elementresponding to a potentially-hurtful overload of predetermined durationto fuse and thereby open said electric circuit, said housing of saidreadily shrinkable material having the outer ends thereof engagingportions of said terminals which are adjacent to but which extendoutwardly from said ends of said support, said portions of saidterminals which are adjacent to but which extend outwardly from saidends of said support having cross sections which are only smallfractions of the cross sections of said ends of said support, saidsupport being acircular in cross section, said terminals making saidcross sections of said ends of said support irregular, and said portionsof said housing of readily shrinkable material closely engaging saidportIons of said terminals which are adjacent to but which extendoutwardly from said ends of said support and also closely engaging saidends of said support despite the irregularity of said ends of saidsupport and despite the disparity between the cross sections of saidends of said support and the cross sections of said portions of saidterminals which are adjacent to but which extend outwardly from saidends of said support, the engagements between said portions of saidhousing of readily shrinkable material and said portions of saidterminals which are adjacent to but which extend outwardly from saidends of said support resisting tilting of said terminals relative to theaxis of said support, and thereby helping said terminals remain inassembled relation with said support.
 9. An electric fuse whichcomprises a support, a terminal adjacent one end of said support, asecond terminal adjacent the other end of said support, a fusibleelement electrically connecting said terminals, a housing of readilyshrinkable material which encloses and protects said fusible element,said housing of readily shrinkable material having portions thereofshrunk into engagement with and enclosing portions of said support andportions of the inner ends of said terminals, said terminals beingconnectable to an electric circuit, said inner ends of said terminalsbeing exposed at the same side of said support, said fusible elementhaving the effective length thereof disposed at said side of saidsupport, a portion of said side of said support which is intermediatesaid terminals being relieved by a notch, said effective length of saidfusible element spanning said notch of said side of said support andthereby being held out of direct engagement with said side of saidsupport, and said inner ends of said terminals extending laterallyoutwardly beyond said side of said support to keep said inner surface ofsaid housing of readily shrinkable material from applying destructiveforces to said effective length of said fusible element, whereby saideffective length of said fusible element is out of engagement with saidnotch of said side of said support and is not subjected to destructiveforces by said inner surface of said housing of readily shrinkablematerial.
 10. An electric fuse which comprises a support, a terminaladjacent one end of said support, a second terminal adjacent the otherend of said support, a fusible element electrically connecting saidterminals, a housing of readily shrinkable material which encloses andprotects said fusible element, said housing of readily shrinkablematerial having portions thereof shrunk into engagement with andenclosing portions of said support and of the inner ends of saidterminals, said terminals extending outwardly through and beyond theends of said housing of readily shrinkable material and being adapted tohold said support, said terminals being connectable to an electriccircuit, said terminals having said inner ends thereof spaced apart apredetermined distance, said fusible element responding to apotentially-hurtful overload of predetermined duration to fuse andthereby open said electric circuit, said support having a metallicsurface adjacent said one end thereof, said support having a secondmetallic surface adjacent said other end thereof, a portion of saidinner end of the first said terminal being planished and being inregister with the first said metallic surface, said portion of saidinner end of said first said terminal being bonded to said first saidmetallic surface in electrical conducting relation, a portion of saidinner end of said second terminal being planished and being in registerwith said second metallic surface, said portion of said inner end ofsaid second terminal being bonded to said second metallic surface inelectrical conducting relation, said first said metallic surface havinga large face-to-face engagement with said one end of said support, saidplanished portion of said inner end of said first said teRminal having arelatively large face-to-face engagement with said first said metallicsurface, said second metallic surface having a large face-to-faceengagement with said other end of said support, said planished portionof said inner end of said second terminal having a relatively largeface-to-face engagement with said second metallic surface, the ends ofsaid housing of readily shrinkable material closely engaging thoseportions of said terminals which are adjacent to and which extendoutwardly beyond said ends of said support, the close engagementsbetween said ends of said housing of readily shrinkable material andsaid portions of said terminals which are adjacent to and which extendoutwardly beyond said ends of said support coacting with saidface-to-face engagements between said inner ends of said terminals andsaid metallic surfaces and also coacting with said face-to-faceengagements between said metallic surfaces and said ends of said supportto resist tilting of said terminals relative to the axis of saidsupport, and thereby helping to maintain said terminals in assembledrelation with said support.
 11. An electric fuse which comprises asupport, a terminal adjacent one end of said support, a second terminaladjacent the other end of said support, a fusible element electricallyconnecting said terminals, a housing of readily shrinkable materialwhich encloses and protects said fusible element, said housing ofreadily shrinkable material having portions thereof shrunk intoengagement with and enclosing portions of said support and portions ofthe inner ends of said terminals, said terminals being connectable to anelectric circuit, the first said terminal having an inner portion thatis in register with and is fixedly secured to said one end of saidsupport and having an outer portion that extends outwardly through saidhousing of readily shrinkable material and beyond said one end of saidsupport and beyond one end of said housing of readily shrinkablematerial to be adapted to hold said one end of said support, said secondterminal having an inner portion that is in register with and is fixedlysecured to said other end of said support and having an outer portionthat extends outwardly through said housing of readily shrinkablematerial and beyond said other end of said support and beyond the otherend of said housing of readily shrinkable material to be adapted to holdsaid other end of said support, said housing of readily shrinkablematerial engaging said inner portions of said terminals, and said endsof said housing of readily shrinkable material extending outwardlybeyond said ends of said support to enclose and intimately engage a partof each of said outer portions of said terminals, the intimateengagement between said ends of said housing of readily shrinkablematerial and said parts of said outer portions of said terminalsenabling said housing of readily shrinkable material to resist tiltingof said terminals relative to the axis of said support and therebyhelping prevent separation of said terminals from said support.
 12. Anelectric fuse which comprises a support, a terminal adjacent one end ofsaid support, a second terminal adjacent the other end of said support,a fusible element electrically connecting said terminals, a housing ofreadily shrinkable material which encloses and protects said fusibleelement, said housing of readily shrinkable material having portionsthereof shrunk into engagement with and enclosing portions of saidsupport and of the inner ends of said terminals, said terminals beingconnectable to an electric circuit, said terminals having said innerends thereof spaced apart axially of said support a predetermineddistance, said fusible element responding to a potentially-hurtfuloverload of predetermined duration to fuse and thereby open saidelectric circuit, said predetermined distance by which said inner endsof said terminals are spaced apart being substantially equal to theeffective length of said fusible eLement, the cross section of saidfusible element being just a small fraction of the cross section of saidinner end of either of said terminals, whereby said inner ends of saidterminals have sufficient mass to cool any arc which forms as saidfusible element fuses to open the circuit, and said spacing apart ofsaid inner ends of said terminals acting to minimize or prevent burningof said inner ends of said terminals when said fusible element fuses toopen said electric circuit.
 13. An electric fuse which comprises asupport, a terminal adjacent one end of said support, a second terminaladjacent the other end of said support, a fusible element electricallyconnecting said terminals, a housing of readily shrinkable materialwhich encloses and protects said fusible element, said housing ofreadily shrinkable material having portions thereof shrunk intoengagement with and enclosing portions of said support and portions ofthe inner ends of said terminals, the first said terminal having aninner end that is in register with and is fixedly secured to said oneend of said support and having an outer portion that extends outwardlythrough said housing of readily shrinkable material and beyond said oneend of said support and beyond one end of said housing of readilyshrinkable material to be connectable to an electric circuit, saidsecond terminal having an inner end that is in register with and isfixedly secured to said other end of said support and having an outerportion that extends outwardly through said housing of readilyshrinkable material and beyond said other end of said support and beyondthe other end of said housing of readily shrinkable material to beconnectable to said electric circuit, a shoulder in said first saidterminal which is intermediate said inner end and said outer portion ofsaid first said terminal, a shoulder in said second terminal which isintermediate said inner end and said outer portion of said secondterminal, and said housing of readily shrinkable material intimatelyengaging said inner ends and said shoulders of said terminals plus partsof said terminals which are outward of but which are immediatelyadjacent said ends of said support, the intimate engagements betweensaid housing of readily shrinkable material and said inner ends and saidshoulders and said parts of said terminals enabling said housing ofreadily shrinkable material to resist tilting of said terminals relativeto the axis of said support and thereby helping prevent separation ofsaid terminals from said support.
 14. An electric fuse which comprises asupport, a terminal adjacent one end of said support, a second terminaladjacent the other end of said support, a fusible element electricallyconnecting said terminals, a housing of readily shrinkable materialwhich encloses and protects said fusible element, said housing ofreadily shrinkable material having portions thereof shrunk intoengagement with and enclosing portions of said support and portions ofthe inner ends of said terminals, the first said terminal having aninner end that is in register with and overlaps and is fixedly securedto said one end of said support and having an outer portion that extendsoutwardly through said housing of readily shrinkable material and beyondsaid one end of said support and beyond one end of said housing ofreadily shrinkable material to be connectable to an electric circuit,said second terminal having an inner end that is in register with andoverlaps and is fixedly secured to said other end of said support andhaving an outer portion that extends outwardly through said housing ofreadily shrinkable material and beyond said other end of said supportand beyond the other end of said housing of readily shrinkable materialto be connectable to said electric circuit, said inner end of said firstsaid terminal being planished to provide a large area of securementbetween said inner end of said first said terminal and said one end ofsaid support, said inner end of said second terminal being planished toprovide a large area of securement between said inner end of said secondterminal and said other end of said support, a shoulder in said firstsaid terminal which is intermediate said inner end and said outerportion of said first said terminal, a shoulder in said second terminalwhich is intermediate said inner end and said outer portion of saidsecond terminal, said shoulder in said first said terminal abutting saidone end of said support to limit the extent to which said planishedinner end of said first said terminal overlaps said one end of saidsupport, said shoulder in said second terminal abutting said other endof said support to limit the extent to which said planished inner end ofsaid second terminal overlaps said other end of said support, and saidhousing of readily shrinkable material intimately engaging said innerends and said shoulders of said terminals plus parts of said terminalswhich are outward of but which are immediately adjacent said ends ofsaid support, the intimate engagement between said housing of readilyshrinkable material and said inner ends and said shoulders and saidparts of said terminals enabling said housing of readly shrinkablematerial to resist tilting of said terminals relative to the axis ofsaid support and thereby helping prevent separation of said terminalsfrom said support.
 15. An electric fuse which comprises a support, aterminal adjacent one end of said support, a second terminal adjacentthe other end of said support, a fusible element electrically connectingsaid terminals, a notch in one side of said support which is spacedinwardly from said ends of said support and which is in register withthe effective length of said fusible element, a housing of readilyshrinkable material which encloses and protects said fusible element,said housing of readily shrinkable material having portions thereofshrunk into engagement with and enclosing portions of said support andportions of the inner ends of said terminals, said terminals beingconnectable to an electric circuit, said inner ends of said terminalsbeing exposed at said side of said support, said fusible element havingsaid effective length thereof disposed at said side of said support,said inner ends of said terminals acting to hold the inner surface ofsaid housing of shrinkable material out of engagement with said ends ofsaid fusible element, said inner ends of said terminals also holdingsaid inner surface of said housing of shrinkable material againstmovement into and engagement with any portion of said effective lengthof said fusible element which could apply destructive forces to saideffective length of said fusible element, said notch being arcuate inside elevation, the deepest portion of said notch being adjacent thelongitudinal center of said effective length of said fusible element,and said fusible element responding to a potentially-hurtful overload ofpredetermined duration to fuse and thereby open said electric circuit.